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We present angle resolved photoemission spectroscopy measurements of the surface states on in-situ grown (111) oriented films of Pb1−xSnxSe, a three dimensional topological crystalline insulator. We observe surface states with Dirac-like dispersion atΓ andM in the surface Brillouin zone, supporting recent theoretical predictions for this family of materials. We study the parallel dispersion isotropy and Dirac-point binding energy of the surface states, and perform tight-binding calculations to support our findings. The relative simplicity of the growth technique is encouraging, and suggests a clear path for future investigations into the role of strain, vicinality and alternative surface orientations in (Pb,Sn)Se compounds.

An effective, simple and practically useful method to incorporate fluorescent nanoparticles inside live biological cells was developed. The internalization time and concentration dependence of a frequently used liposomal transfection factor (Lipofectamine 2000) was studied. A user friendly, one-step technique to obtain water and organic solvent soluble Er(3+) and Yb(3+) doped NaYF4 nanoparticles coated with polyvinylpyrrolidone was obtained. Structural analysis of the nanoparticles confirmed the formation of nanocrystals of the desired sizes and spectral properties. The internalization of NaYF4 nanoparticles in HeLa cervical cancer cells was determined at different nanoparticle concentrations and for incubation periods from 3 to 24 h. The images revealed a redistribution of nanoparticles inside the cell, which increases with incubation time and concentration levels, and depends on the presence of the transfection factor. The study identifies, for the first time, factors responsible for an effective endocytosis of the up-converting nanoparticles to HeLa cells. Thus, the method could be applied to investigate a wide range of future 'smart' theranostic agents. Nanoparticles incorporated into the liposomes appear to be very promising fluorescent probes for imaging real-time cellular dynamics.

The authors demonstrate that by lowering deposition temperature of ZnMnO films (T<500°C) they can avoid Mn clustering and creation of inclusions of Mn oxides, which are frequently formed in ZnMnO layers grown by high temperature methods. Low temperature growth is achieved using atomic layer deposition and organic zinc and manganese precursors.

Magnetic nanoparticles of Fe 3 O 4 doped by different amounts of Y 3+ (0, 0.1, 1, and 10%) ions were designed to obtain maximum heating efficiency in magnetic hyperthermia for cancer treatment. Single-phase formation was evident by X-ray diffraction measurements. An improved magnetization value was obtained for the Fe 3 O 4 sample with 1% Y 3+ doping. The specific absorption rate (SAR) and intrinsic loss of power (ILP) values for prepared colloids were obtained in water. The best results were estimated for Fe 3 O 4 with 0.1% Y 3+ ions (SAR = 194 W/g and ILP = 1.85 nHm 2 /kg for a magnetic field of 16 kA/m with the frequency of 413 kHz). The excellent biocompatibility with low cell cytotoxicity of Fe 3 O 4 :Y nanoparticles was observed. Immediately after magnetic hyperthermia treatment with Fe 3 O 4 :0.1%Y, a decrease in 4T1 cells’ viability was observed (77% for 35 μg/mL and 68% for 100 μg/mL). These results suggest that nanoparticles of Fe 3 O 4 doped by Y 3+ ions are suitable for biomedical applications, especially for hyperthermia treatment.